The Coast Starlight's frequency was eventually increased to daily, and the Puget Sound was replaced by the Pioneer; meanwhile, the Mount Rainier was the one constant train on the corridor, although for a time in the late 1970s, it only ran northbound while the Pacific International served the route southbound.

In the early 1990s, the states of Washington and Oregon became interested in developing the corridor as a high-speed rail line. The first step toward the goal was extending the Mount Rainier to Eugene in October 1994.